Make your own observations
Start with the equipment you have and a quantity you can measure. Decide what each model predicts before you collect the readings.
Measure Earth with two or three shadows
Measure upright height and signed noon shadow angles at separated sites. Two sites estimate circumference; a third non-symmetric site tests competing angle curves.
Vertical rods with plumb-line checks · Level measuring surface, ruler and clock · Site coordinates and northward meridian distancesObserve one target from several heights
Keep the target and distance fixed while changing camera height. Record which named parts remain visible, then compare the predicted hidden height.
Tripod and measurable camera-height settings · Target with known vertical features · Distance baseline and time/weather recordCompare sunset from two heights
Record the horizon crossing from two measured heights at one location. A higher observer can retain a view after the lower observer loses it.
Two observers or synchronized fixed cameras · Measured heights above the same horizon surface · UTC-synchronized clocks and a safe solar recording setupPhotograph star trails in both hemispheres
Record a timed exposure with known latitude and camera orientation. Compare the trail’s centre, direction and angular motion with the selected sky geometry.
Tripod and timed camera exposures · Clock, coordinates and compass reference · Dark sky and identifiable starsMeasure latitude with Polaris
Measure the North Star’s altitude from a level horizon. Compare it with latitude while accounting for Polaris’s offset from the celestial pole.
Angle instrument with a level reference · Location latitude and observation time · Unobstructed northern skyRecord the shadow during a lunar eclipse
Photograph the same eclipse sequence at consistent scale. Compare contact progression and shadow shape while keeping ordinary lunar phases separate.
Tripod and camera with repeatable focal length · UTC clock and location · A lunar-eclipse event with the Moon above the horizonObserve a Foucault pendulum
Compare the swing plane’s slow turn with the prediction for the instrument’s latitude. A large, well-controlled installation is more useful than a short improvised pendulum.
Museum or other suitable Foucault installation · Known latitude and marked swing-plane reference · Clock and observation logObserve a predicted satellite pass
Compare published orbit predictions with a visible or received pass. Log time, direction and signal changes across more than one passage.
Public orbital-element record and pass predictions · Clock and coordinates · Camera, binoculars or a receive-only radio setupObserve atmospheric changes over water
Repeat the same long-distance target record at several camera heights and times, pairing visibility changes with atmospheric measurements.
Fixed target and measured heights · Several thermometers or a documented profile · Tripod, clock, weather and water-level recordCalibrate a lens before measuring a horizon
Photograph straight references with fixed lens settings, then compare their recorded curvature at several positions in the frame.
Camera and stable straight-line target · Tripod and fixed focus/focal length · Original files and a level referencePrint an Earth observation record
Prepare one record for predictions, settings and raw measurements before an observation. Keep alternative predictions in the same units.
One named observation and location · Time, units and instrument settings · Space for raw readings and uncertainty